Noise after total knee arthroplasty has limited effect on joint awareness and patient reported clinical outcomes

BackgroundSome patients complain of noise after total knee arthroplasty (TKA). Controversy still exists how the noise affect the clinical outcomes including joint awareness after TKA. Forgotten Joint Score-12 (FJS-12) measures the clinical outcomes focusing on joint awareness after surgery. The Knee Society Scoring System-2011 (KSS-2011) includes questionnaires for satisfaction, expectation, and functional activities. The aim of this study is to clarify the relationship among FJS-12, KSS-2011 and the noise. Furthermore, the relationship between FJS-12 and KSS-2011 was validated. MethodsUsing the FJS-12 and KSS-2011, 295 knees from 225 patients who underwent TKA was retrospectively evaluated. Noise perception was evaluated by a questionnaire with five grades which is a method that follows the questionnaire form of FJS-12 [“Are you aware of the noise of your artificial joint?” ; never, almost never, seldom, sometimes, mostly]. The correlations among FJS-12, KSS-2011, and noise were analyzed. In addition, patients were divided into four groups based on the mechanism of their implant [cruciate retaining, posterior stabilized, cruciate sacrificed, and bicruciate stabilized (BCS)]. FJS-12, KSS-2011, and noise were compared among the groups. ResultsA strong correlation was observed between FJS-12 and the total score of KSS-2011 (0.70; P < 0.001). FJS-12 also was correlated with KSS-2011 subcategories for “symptoms,” “satisfaction,” and “standard activities” that these correlation coefficients were approximately 0.60. Noise was limited to have weak correlations with FJS-12 (0.28; P < 0.001) and KSS-2011 (0.20 P < 0.001). With comparison among the TKA mechanisms, BCS showed significantly better KSS-2011 and greater range of movement but worse noise scores.ConclusionsNoise perception after TKA had limited effect on joint awareness and clinical outcomes. FJS-12 was correlated strongly with KSS-2011 and associated with satisfaction, residual symptoms, and daily activities as assessed by KSS-2011 subscores.